Abstract
The main objective of this study was to check the validity of using a γ-camera as an alternative to a thyroid uptake probe for measuring the γ-count from 0.925-MBq (25 μCi) and 1.85-MBq (50 μCi) 131I capsules before administration to patients. Methods: Ten sets each of 0.925- and 1.85-MBq 131I capsules received from the Board of Radiation and Isotope Technology, Department of Atomic Energy, India, were counted individually using a thyroid uptake probe for 10 s following institutional protocol, keeping an 8-cm gap between capsules. Each set was also scanned by a scintillation γ-camera for 100 s. The scans were analyzed by drawing identical regions of interest around each set of 0.925- and 1.85-MBq 131I capsules, and the correlation between the camera-based and probe-based methods was determined. By either method, capsules having counts within 2 SDs of the mean were considered acceptable for administration to patients. Results: The correlation between the two methods was good (r > 0.95). Conclusion: The camera-based method of counting 131I capsules is easy and saves time, compared with the probe-based method, as an entire set of capsules can be scanned in a single acquisition. The camera-based method can show whether a batch of 131I capsules is uniform and therefore eliminate the time-consuming counting of individual capsules with a thyroid uptake probe.
Footnotes
Published online Nov. 10, 2017.